-- Copyright 2012 by Till Tantau -- -- This file may be distributed an/or modified -- -- 1. under the LaTeX Project Public License and/or -- 2. under the GNU Public License -- -- See the file doc/generic/pgf/licenses/LICENSE for more information -- @release $Header$ -- Imports local declare = require("pgf.gd.interface.InterfaceToAlgorithms").declare --- -- @section subsection {Controlling and Configuring Force-Based Algorithms} -- -- All force-based algorithms are based on -- a general pattern which we detail in the following. Numerous options -- can be used to influence the behavior of this general pattern; more -- specific options that apply only to individual algorithms are -- explained along with these algorithms. -- -- The vertices are initially laid out in a random configuration. -- Then the configuration is annealed to find a configuration of -- minimal energy. To avoid getting stuck in a local minimum or at a -- saddle point, random forces are added. All of this makes the final -- layout extremely susceptible to changes in the random numbers. To -- achieve a certain stability of the results, you should fix the -- random seed. However, in the recent past Lua has switched its -- random number generator, which means that you won't get the same -- sequence of random numbers as in a previous version, even for -- identical seed. If you rely on the long-term stability of vertex -- placement, you should consider using a different layout. With the -- spring layout you have to assume that the layout will be random. -- -- @end